The longterm goal of this project is to understand the mechanisms controlling the motility of spermatozoa. Specifically, this project will define relationships between flagellar motility and the biochemical properties of the flagellar components by studying the interaction of dynein arms and outer doublet microtubules. Monoclonal antibodies, specific for each of the several dynein peptides, will be used to functionally map the dynein arm. Extremely sensitive immunoautoradiography techniques will be used to identify the antigenic specificities of each monoclonal antibody. Two general methods will be employed. First, the quantitative reactivation of sea urchin spermatozxoa and a microtubule sliding assay will be used to test the effects of various monoclonal antibodies on flagellar movement parameters. Since the binding specificity of each of the antibodies will have been determined, any perturbation of movement will be directly related to the specific substructure that the antibody binds. The second method will be a radioactive-association assay in which in vitro dynein-microtubule interaction will be quantitated. Monoclonal antibodies, of known specificities, will be used to interfere with these associations, and thereby identify those components of the dynein complex that are involved in various microtuble associations. These experiments will employ the simple sea urchin spermatozoan flagellum as a model system in order to provide important information about the movement of all uekaryotic cilia and flagella, including human spermatozoa.